Refining of animal and vegetable oils



Aug. 1l, 1942. B, CLAYTON v 2,292,822

` REFINING oF ANIMAL AND VEGETABLEQILS Filed'Aug. a,v 1941 Berg/ammUlayon,

a 74m, mavwum www Patented Aug. 11, 1942 Benjamin Clayton, Houston,Tex., assignor to Rening, Inc., Reno, Nev., a corporation of NevadaApplication August 8, 1941, Serial No. 406,062

14 Claims. (Cl. 26o-425) This invention relates to a process of refiningglyceride oils, and more particularly to a process in which the color ofthe oil is reduced prior to neutralization of the free fatty acids inorder to enable neutralization to be carried out in a manner'which doesnot causek saponification of neutral oil.

This invention is particularly adaptable to highly colored oils, such ascottonseed oil, but is advantageous for refining various other oils,such as soya bean oil, corn oil, sesame oil, rapeseed oil,

etc., and may be employed in refining other glycl eride or fattyoilssuch as animal and ilsh` oils. Many oils, particularly cottonseedoil, are highly colored. and this color must be reduced to produce acommercially acceptable oil. It has been Vthe practice in refining suchoils to'empl'oy a ried on so as to assist in removing color from theoil.` Thus, degumming agents having bleaching properties such` as oxygenliberating materials,

caustic alkali., usually caustic soda, as a reiiningv reagent and use aconsiderable excess of such reagent for reaction with color impuritiesin the oil. However, caustic alkalies saponify neutral oil and, whenemployed in the necessary excess, cause substantial refining losses dueto saponication of neutral oil. Other neutralizing reagents, such assodium carbonate, trisodium phosphate, sodium silicate, etc., orequivalent potassium salts, will neutralize the free fatty acids,

Abut will not substantially reduce the color of the oil. The same is`true of such neutralizing agentsas ammonia or amines, for example,methylamine, ethylamine, or triethanolainine. vIn general, neutralizingreagents other than caustic alkalies have the advantage ofnot attackingneutral oil, but have not been extensively employed because they do notsubstantially reduce the color of the oil. Bleaching agents, or coloradsorbents. such as acid treated clay, iullers earth, activated carbon,etc., when employed in bleaching processes subsequent to treating withneutralizing re.. agents other than caustic alkalles, are also no It hasbeen foundv that the color adsorbents ljust referred to are eilectiveto" reduce the color of the oil to within commercial limits,'if employedprior to neutralization treatments. Vegetable oils" in general, however,contain substantial'.

quantities of gummy materials, such as phosl'- phatides, proteins,resins, etc., which interfere with fthe'employment of the bleaching.materials referred to.A In the presence of such gums, large amounts ofcolor adsorbents are necessary. Also,

the 'gums interfere .with the separation of the adsorbents from the oiland cause a. large-amount of valuable oil to be retainedtherein. Itispossible to recover a portion of this oil from the adsorbent,

butin the presence of the gums referred the oil 1s `o1' poor quality. Bytreating an oil which has been denuded of gums with a color adsorbent,it has been found that the color of the oil issubstantially reduced, andthat the amount of adsorbent necessary and the amount of oil retained inthe adsorbent are markedly reduced.

Also, a major portion of this oil can be recovered.

as high quality oil by treating the lter cake with an oil solvent. Thepresent invention, therefore, contemplates removing gums from the oilprior to the employment of color adsorbents or starting with an oilwhich is substantially free of gums and treating this oil with a coloradsorbent.

In addition, the degumming step may be car'- Afor example, solutions ofhydrogen peroxide, organic peroxides, alkali metal or alkaline earth`metal peroxides, hypochlorites, Aperborates, per-- carbonates,persulphates, etc., may be yemployed as part or all of the Adegummingagent to produce` a degummed oil of lighter color so as to reduce theamount of color adsorbent necessary to be used in the following step.Furthermore, certain degumming agents which do not liberate oxygen, forexample, boric acid, have color removing properties whenthe mixture ofcrude oil and degumming agent is subjected to relatively hightemperatures. With some oils suiiicient color re-V duction may beaccomplished by solutions of ther v abovementioned forming part or allof the degumming agents so that treatment with an adsorbent afterdegumming is rendered unnecessary.

As indicated above, effective color reduction can thus be produced, andthe oil conditioned for treatment with neutralizing agents which do notsubstantially-reduce color. It is preferred to employ anon-saponifyingneutralizing agent* which will not lattack neutral oil.However, caustic alkalies in amounts substantially equivalentto the freefatty vacids can be Aemployed with or without additional non-saponifyingneutralizing agent without substantial attack on neutral oil. Also, thesoap stock resulting from neutralization'is relatively free from gumsand coloring materials, so that entrainment of neutral oil' therein islessened and such'entrained oil can be recovered as high quality oil.

It is, therefore, an object of the present invention to 'provide aprocess of refining animal and vegetable Oils in which oilssubstantially free of gums are treated with bleaching agents prior toneutralizing the free vfatty acids thereof.

Another object of the invention is to provide a process of refiningglyceride oils in which refining losses are minimized by preventingsaponiflcation of neutral oil in the neutralizing step while produoingaqoil ofaocoptable color.; A furthenobiect of e inventionlis tovprovide aprocess of refining fatty oils in which the oil is bleached in a manneravoiding substantial losses of neutral oil and then subjected toneutralization and separation of resultin'g'soapstbc; in"

which steps saponiiication of neutral oil and entrainment of oil in thesoap..stock can,be largely prevented.

Other objects and advantages of the invention will appear in thefollowing deecription of the invention given in connection with 'theattached drawing which is a diagrammatic showing of'an apparatussuitable for carrying out a preferred process.' f -The l`apparatusriisclosedfis' capable of' being usedto carry out ay process in whichthe oil vis continuously degummed," treating with a color adsorbent-toreducethe color thereof, then 'continuously treated ywith e;neutralizing agent,'and the resulting soap stock continuously separatedfrom the 011:' --As will appearbelow, certain' of the steps referred`to'maybe carried on as'batch operations, and' still provide an improvedprocess..

"Referring more'particularly to the drawing, crude bilis withdrawnfromasource of supply shownas aftank HJ by a pump II and forced througha'heat 'exchanger 'I2 to a'mixlng device It` The heatexchangedevice I2may include afooil -I4- through-which-theoil' is passed and erasing"I5'surrounding the' coil I4. Any suitable'lr'eating medium may becirculated through the casing` I5 inorder to heat the' oil. A de'-gummingreagent is withdrawn from asource of supply'shown as a tank' I6'by apump I1 and delivered to themixing' device I3." The pumps lHani'l:I1 are shownas being driven by a varia- 'blespeed eiectricmotor-'with' avariable speed device-18' positioned between' the motor and the pump -II: .'Ihis'provides for delivering accurately proportiohed'streams' of"oil' and degumming reagent'under pressure to'the' mixer I3, but anyother suitable type of proportioning mechanism Lmay be employed in lieuthereof; "I'he mixer I3 is 'preferably "closed -from the -'atmosphereand ofthe flow type in' which a'streambf degummin'g reagent isiniectedatright angles into a flowing stream of-oiL-'but may-bemany-suitable type of flow mixer'such as' a"closed'mechanical''agitator. The degumming reagent, when admixed 'with the oilin the mixerI3 precipitates the gummy materials 'contained inthe 'oil and the agentis preferably passedthrough a -second heat exchange device 20, whichmaybe similar to the heat exchange device l2-and delivered to acontinuous eentrifugalseparator 2l. 'I'he separator 3l ispreferablyofthe heated type similar to that disclosedinPatent No., 2,100,277.,granted Novem'- ber 2 3, 1937, butzmay be of any type of separator`capable'pf sc eparatingl gums from oil. 'I'he gums are dischargedl fromthecentrifugal separator as the heavy eilluent, through a spout 22 intoa receiver23, and refined oil i's discharged as the iight 'emeht'through epipe za.

'I'he oil discharged'frox'n the centrifugal separator 2i'is'subs'tantia'lly free of gummy mate- 4rials and may-'be'd'irectly'di's'charged into a mixing tank 25 iii wlch it is mixed with'a bleaching or color reducing agent such as an adsorbent earth. Asecond tank 28 is shown so that the oil may be delivered into one ofthese tanks, while another body of oil is being mixed with the bleachingagent in the other tank and discharged therefrom. Thus, by opening thevalve in the pip e21 connected to the tank 25 and closing the v`alveinthe pipe 28co'nnected tothe tank 25, oil may be delivered from lthecentrifugal separator 2| into the tank 25. Conversely, by closing thevalve on the pipe 21 and opening the Valveon the pipe 2 8, oil may bedischarged into the tank 28. Each olf the tanks 25 and 28 maybeipiovlded with an agitator 28 driven from any 15..'suitable source ofpower through a pulley or Asprocket 20. Tanks 25 and 2l may also beprovided with heat exchange coils 2I through which any'deslrable heatingor cooling medium may be circulated in order to maintain the oil in thetanks at a desired temperature. The tanks 25 andv 28 are preferablyclosed to the atmosphere in order-toprevent contact between theatmosphere and the heated oil in the tanks and also prevent air frombeing stirred into the oil during agitation thereof. 'Adsorbent earth orother bleaching agents may be introduced into. the

tanks through a hopper 32 for each tank. Thus, mixing with the bleachingagent and withdrawal of oil from one tank may take place simultaneouslywith introduction of oil into the other tank. Alternatively, mixing andintroduction of oil may take place simultaneously in one tank while oilis being withdrawn from the other tank.

'i The oil can be withdrawn from the tanks 25 and 26 b'y means of a pump82 driven by a motor 84.v1 By opening the valve in the pipe 25 connectedto the tank 25 and closing the valve in the pipe"'36 connected to thepipe 28,' oil is withdrawn'from the tank 25; and conversely, closing thevalve'in the pipe 85 and opening the valve in the pipe .36 allows oil tobe withdrawn from the tank'26. 'Ihe agitator 29 in the tank from whichthe oil is being withdrawn is preferably maintained in motion duringwithdrawal so as to maintain the bleaching agent in substantiallyuniform admixture with the oil.

'The mixture of oil and bleaching material is then'delivered to a filterpress 51 or a lter .press 38. vTwo filter presses have been shown, in'order to provide for filtration in one filter press while the other isbeing cleaned. As many filter presses as necessary to provide forcontinuous filtration of oil or a continuous filtration system may beemployed. The filtered 'oil from either of the filter presses 31 or 38is discharged therefrom through a pipe 39 into a container 40 which ispreferably a. closed tank provided .with a -vent 4I. The ltered oilcollected in thel tank 40 is'free of gummy materials and is of reducedcolor, but still contains free fatty acids. The filtered oil may bewithdrawn from the tank 40 by a pump 42 and passed through `a heatexchanger 43 to a mixer 44. A neutralizing'agen't' is'withd'rawn from asource of supply shown as a tank 45 by a pump 46 and delivered to' themixer 44. The pumps 42 and 46 may be driven by a variable speed electricmotor 41 with` a variable speed device V48 positioned between the motorand the pump 42, although any other apparatus capable of deliveringaccurately proportioned streams to the mixer 44 may be employed. 'I'hemixer 44 is also preferably 'of the flow type in which a stream of theneutralizing reagent is injected at right angles into a flowing streamof the oil, but, as in the case of vacuum y from the vacuum chamber 50by mixer I3, may be any type of now mixer such as a closed mechanicalagitator. The neutrallz' ing agent reacts with the free fatty acids ofthe oil to produce soap stock, and the mixture of oil and soap stock ispreferably passed through another heat exchanger 49 and delivered into avacuum chamber 50.

The vacuum chamber 50 is preferably provided with a heating jacketthrough which any desired heating medium may be circulated and with asteam distributor positioned in the lower portion of the tank to enablesteam, preferably superheated, to be passed through a body of oilcontained in the. vacuum chamber 50. The chamber 50 is employed toremove vaporizable material, including at least a portion y of the waterin admixture therewith, and any gases such as air or carbon dioxideoccluded in amount of water, it is many times advantageous to dry thisoil before delivering it to the mixing tanks 25 or 26. This may beaccomplished by delivering the oilto a dehydrating chamber through apipe 16 by closing the valve 11 in the pipe 2l and opening the valve 18in the pipe 15. The chamber 15 may be provided with a heating coil 19and a vacuum pump 8| connected to the chamber through a condenser 82 anda receiver 83 lfor removing moisture from the oil. The dried degummedoil 'may be continuously removed from the dehydrating chamber 15 by apump 54 and returned tothe pipe 24 for delivery to the mix the soapstock particles. Vapors and gases are l 'vaporizable' materialsincluding water are con` densed material may be withdrawn from thereceiver 51, for example, by means of a pump (not shown) through a pipe58'. A vacuum pump 59 connected to the receiver 51 is provided forwithdrawing uncondensed 1gases and maintainingja vacuum in the vacuumchamber 50. The mixture of oil andsoap stock is preferably deliveredlinto the vacuum chamber 50 through nozzles SII positioned so as todirect the mixture against the heated walls of the vacuum chamber sothat the 40 mixtureilows` down the walls as a thin film.

This provides for eflicient separation of gases and vapors from themixture-and further provides for unobstructed passage for thel gases andvapors inwardly and \upwardly through the vacuum chamber to the pipe 53so asto minimize en` trainment in said gases and vapors. y

The dehydrated mixture of oil and soap stock, which is substantiallyfree of gases, is withdrawn stock therein. Alternatively, the weightingliquid ,and bases.

ing tanks 25 and 26.

In the preferred process carried out in the above described apparatus,effective degumming with most oils is produced by preheating the oilfrom thevtank I0 in the heat exchanger l2 tor a temperature between 110and 160 F.,prior to admixture with a a degumming reagent. With otheroils, it has been found most eifective to mix at lower temperatures, forexample, temperatures from 70 to 100 F., 'and then heat lto a desired ytemperature of separation in the heat exchanger 20, in which case theheat exchanger v I2 may be eliminated for the lower temperatures ofmixing. As isclosed in the copending application of Benjamin H. Thurman,Serial No. 2l3,700,.iiled June 14, v1938, there is an optimumtemperature and treating time between mlxing'and separation for eachoilbeing degummed, such that no definite range of temperatures vorltreatingAtimes ca'n be "given for all oils contemplated -by the present process.The temperature of separation and treatment and-time of treatment willnot only dependupon the particular oilbeing treated but- Y also upon thetype of degumming reagent employed. The degumming reagentmay be water.

alone,aqueous solutions of neutral salts or weak acids or bases ordilute solutions of strong acidsV The degumming reagent also preferablyincludes a soluble alkali thiosulfate or thiocyanate, asdisclosed in thecopending application of Benjamin H. Thurman, Serial No. 248,355, filedDecember 29, 1938, as more liquid gums are thereby produced and less oilis entrained in the gums separated from the. oil in the separator 2l.Thel `continuousdegumming operation disclosed 'above is preferable, as asubstantially complete'sepaapump 5I and 50 Vdelivered through a pipe 62,heat exchanger 53 y may be delivered into the pipe 52 between Ithe gpump 6I and the vheat exchanger 63 through a pipe 69 orcentrifugalseparator 65 mayhave prothe tankSB ,directly intothecentrifugal bowl. `In any case, the separator is preferably of theheated/typel disclosed in the patent above referred to, although anytype of centrifugal sepa-l rator capable of separatingthe'soapstockfrcmthe oil may'beemployed, Soap stock, along-withlvision'for denvering the weighting liquid from 959 ratiorrofy the gumsfrom the oil is effected, and the entrainment of neutral oil in the`gums is markedly reduced., However, it is possible to produce adegummed oil in which either-the mixing or separation steps, or both,are batch operations. Thus, the oil and-degumming reagent, such as,water, may be yadmixed in a tank and the gums allowed to settle fromthe oil,A or ya continuous, mixing step maybe combined 'with a gravitysettling steplor a continuous centrifugalsepal i' ration step combinedwith a batch mixing step.-

Such batch operations, however, tend to 'set greater losses due toentrainment ofo'il in the dependy upon the process employed, the type ofoil.`

weighting liquid, is` discharged as the heavy eillu- 'l foots. Theamount of degumming -reagent will being treated, and the nature of therdegumming reagent, andmay range between `wide limits,A for example,from` 1% 'to 50%.

chloritesabo've-mentioned, in whichcas'e it may be possible` toeliminate a subsequent step -of- The degumming agent mayv include -asoluble bleaching agent such as the peroxides or yhypohigh temperaturetreatment in the presence of boric acid as the degumming agent has amarked eilect in reducing color so as to reduce the amount ofsubsequently used color adsorbent or to make it possible to eliminatesuch a subsequent step. Ordinarily, any high temperature treatment ofoils containing gums and coloring matter tends to "set the color in theoil so as to render its subsequent removal more diiiicult. However, thereverse is true when employing a solution of boric acid as a degummingagent alone or in combination with other degumming agents. The hightemperature referred to will usually range between 200 and 550 F.,depending upon the amount of color it is necessary or desired to remove,and may be secured by preheating the oil in the heat'exchanger I2 orheating the mixture in the heat exchanger 20. Separation may in somecases be performed at the high temperature, but the mixture may becooled before separation, if desired. l

The color -adsorbent employed as a bleaching agent to bleach thesubstantially gum-free oils prior to alkali refining will also dependupon the nature of the oil being treated. For example, with highlycolored cottonseed oil an extremely active bleaching agent, such as acidtreated clay,

temperatures. so as to assist in vaporizing water and other vaporizablevmaterials from the mixture of oil and soap stock and also to assist inmay be required, while with oils containing less I colors, such as cornoil, a less -drastic bleaching agent such as fullers earth or evenactivated carbon may be suflicient. Other examples of adsorbents whichmay be employed depending upon the nature and amount of color to beremoved are aluminum oxide, aluminum silicates. diatomaceous earth, etc.'I'he temperature of treatment of the oil with thesolid bleaching agentwill also vary with the oil being treated and the amount of colorreduction necessary. Certain of the oxygen liberating bleaching agentsmay likewise be employed with the color adsorbents, if the color isdimcult to remove. Thus, temperatures from substantially roomtemperatureVi. e., 70 F. for light colored oils, up to as high as 200 to400 F. for extremely dark colored oils may be required. This temperaturemay be adjusted by means of the heat exchange coils 3| located in thetanks 26, or, alternatively, a heat exchange device may be employedbetween the centrifugal separator 2| and the tanks and 26. The oil maybe a1- ternately mixed with the bleaching agent in the tanks 25 and 26and delivered to the filter` presses 31 and 38 or a continuous mixingstep may be,

employed. The iilter presses may be of any conventional type capable ofseparating the bleachlng agents along with adsorbed color from the oil.Also, it is possible to separate the bleaching agent from the oil bycontinuous ltering devices or by centrifugal separation, for example,continuous centrifugal separation with a iiushing liquid forcontinuously washing the separated bleaching agent along with adsorbedcolor impurities from the centrifuge.

The heat exchanger 43 is employed to provide' an optimum temperature ofmixing between the neutralizing agent and the oil. This temperature willdepend upon the oil being treated and the neutralizing agent.Preheatingis desirable in some cases, in which case mixing may takeplace at temperatures between approximately 110 and 160 F., while inother cases mixing at relatively low temperatures, for example, betweenand 100 F. produces best results. The heat exchanger 49 may be employedto add heat to the mixture, particularly if mixing is at low driving oi!gases such as air occluded in the oil or carbon dioxide produced duringneutralization. If preheating is employed, the heat exchanger 49 may beeliminated, and,the mixer M positioned closely adjacent the vacuumchamber 50. By positioning the mixer 44 closely adjacent the vacuumchamber 50. the vacuum may extend into the mixer 4Iv such that mixing isunder vacuum conditions. Alternatively, the oil and neutralizing agentmay be delivered as separate streams directly into the vacuum chamber Ilso as to provide for mixing therein. The heating jacket 5! for thevacuum chamber 50 may be employed to maintain a desired treatingtemperature in lthe vacuum chamber 50, and also superheated steam may bepassed through a body of oil and soap stock in the chamber 50 to assistin carrying ofi the gases and vaporizing materials and supply additionalheat to the mixture.

It is difficult to separate soap stock produced by neutralizing degummedoil from the oil without leaving a large amount of soap stock in the oilor a large amount of oil entrained in the soap stock. By dehydrating themixture of oil and soap stock in accordance with the preferred processand then introducing a weighting liquid into the mixture shortly beforeit is delivered to the separating zone of the continuous centrifugalseparator, an effective separation of the oil and soap stock can beobtained to produce a clean oil and a soap stock containing very littleentrained oil. In this process, the heat exchanger 63 may be employed toadjust the temperature of the oil-soap stock mixture to that found mosteffective for separation of the oil being treated. This temperature willordinarily vary from to 160 F. If the oil withdrawn from the vacuumchamber 50 is at the most effective temperature for separation for theparticular oil being treated, the heat exchanger 83 may be eliminated,although with certain oils it has been found more effective to introducethe water into the oil-soap stock mixture through the pipe 69 so thatthe mixture of oil-soap stock with the weighting liquid is passedthrough the heat exchanger 63, irrespective of whether this heatexchanger is employed to produce a change in temperature of the mixture.Although the vacuum treatment followed by continuous centrifugalseparation in the presence of a weighting liquid is preferred, it ispossible to settle the soap stock from the oil. This settling step maybe combined with continuous mixing. as above described, or both themixing and settling steps may be carried on as batch operations. Sincenon-saponifying neutralizing reagents or no substantial excess ofsaponifying neutralizing reagents are employed, no substantial attack onthe neutral oil is produced, even in batch alkali refining operations.If sodium carbonate is employed as the neutralizing reagent in a batchoperation, it is preferred to mix under vacuum conditions, or at leastsubject the resulting mixture of oil and soap stock to vacuum conditionsprior to settling, in order to eliminate carbon dioxide. The presence ofa vweighting liquid is also desirable in batch settling steps, in whichcase the weighting liquid is usually a relatively concentrated aqueoussolution of sodium chloride or other alkali metal salt. The soap stockseparated by a settling operation usually contains a large amount ofentrained neutral oil,

escasas but because of the absence of substantial amounts of gums orcoloring material in the soap stock, this oil may be recovered as highquality oil from the soap stock by diluting the same with water andagain settling or centrifugally separating or by solvent extraction withan oil solvent..

It is also possible to employ with advantage vaporizable neutralizingreagents which do not attack neutral oil, for example, ammonia or aminessuch as referred to above. With such neutralizing agents, the soap stockproduced is ordinarily flowable and no weighting liquid is usuallynecessary. Also. vacuum treatment of the mixture is omitted, as suchtreatment would remove the neutralizing reagent to again leave freefatty acids in the oil. 'Ijhe soap stock produced by ammonia, amines orother vaporizable neutralizing reagents is preferably continuouslycentrifugally separated from the oil, but may valso be settledtherefrom. When employing such vaporizable neutralizing reagents in theprocess, the mixing and separating is preferably carried on in a closedsystem under pressure to prevent loss of neutralizing agent. Oneadvantage of such neutralizing agents 'is that the soap stock producedmay be subjected to vacuum treatment to remove the neutralizing agentfor reuse in the process and also to produce fatty acids.

It will be seen that I have provided a process wherein the oil isneutralized under conditions in which there is no substantial attack onthe neutral oil so as to reduce refining losses due to saponification ofneutral oil. Thus refining reagents which will not attack neutral oilcan beemployed. and also caustic alkalies can be employed in amountssubstantially chemically equivalent to the free fatty acids contained inceride, thereafter neutralizing the free fatty acids of said glycerideunder conditions preventing substantial saponification ofneutralglyceride, adding a solution of an ,alkali metal salt to theresulting mixture of oil and soap stock, and

thereafter neutralizing the free fatty acids of said glyceride underconditions preventing substantial saponication of neutral glyceride,adding a solution of an alkali metal salt to the resulting mixture ofoil and soap stock,land thereafter` continuously centrifugallyseparating the soap stock from said glyceride in the presence l of saidadded solution.

3. The process of rellning glyceride oils and fats .containing gums,color impurities and free a solution of an alkali metal salt to theresultthe ons. The neutralizing without substantial attack on theneutral oil is made possible by removing color impurities from the oilprior to neutralization. Thus, it is unnecessary to employ causticalkalies in excess to reduce color. The removal of color impuritiesprior to neutralization by treatment with color adsorbents `myco-pending application, Serial No. 248,330,

filed December 29, 1938.

While, I have disclosed the preferred embodiment of my invention, it isunderstood that the details thereof maybe varied within the scope of thefollowing claims.

I claim:

l. A process of refining glyceride oils and fats containing gums, colorimpurities and free fatty acids, which comprises, admixing a stream ofan aqueous degumming reagent with a stream of said glyceride toprecipitate gums therein, delivering the resulting stream to acentrifugal separator and continuously centrifugally separating theprecipitated gums from said glyceride, treating said glyceride with anadsorbent material for color impurities and removing said adsorbentalong with said color impurities from said glying mixture of oil andsoap stock, and thereafter separating the soap stock from Isaid glyfceride by difference in specific gravity in the v presence of said addedsolution.

4. 'Ihe process of refining glyceride oils and fats containing gums,color impurities and free fatty acids, which comprises, removing saidgums` from said glyceride, thereafter treating said glyceride with anadsorbent material for color impurities and removing said adsorbentalong with said color impurities from said glyceride, thereafterneutralizing the free fatty acids of said glyceride with an aqueoussolution ofV sodium carbonate to prevent substantial saponiiication ofneutral g1yceride,.adding a solution of an alkali metal salt lto theresulting mixture o f oil and soap stock, and thereafter separating thesoap stock from said glycerides by difference in specific gravity in thepresence of said added solution.

5. The 4process of refining glyceride oils and fats containing gums,color impurities and free fatty acids, which comprises. removing saidgums from said glyceride, thereafter treating said glyceride with anadsorbent material for color impurities and removing said adsorbentalong with Said color impurities from said glyceride.thereafterneutralizing the free fatty acids of said glyceride with anon-saponifying alkali, adding a solution of an alkali metal salt to theresulting mixture of soap stock, and thereafter separating the soapstock from Said glyceride by difference in specific gravity in thepresence of said added solution.

6. The process of refining glyceride oils and fats containing gums,color impurities and free fatty acids, which comprises, removing saidgums from said glyceride, thereafter treating said glyceride with anadsorbent material for fcolor -stock while preventing substantialsaponification of neutral glyceride, rehydrating said mixture ofglyceride and soap stock and separating said soap stock from saidglyceride by difference in specific gravity.

7. The process of refining glyceride oils and fats containing gums,color impurities. and free fatty acids, which comprises. removing saidgums from said glyceride, thereafter treating said Y glyceridewith anadsorbent materiab for color impurities and removing said adsorbentalong with said color impurities from said glyceride, thereafterneutralizing the free fatty acids of said glyceride with sodiumcarbonate, adding a solution of an alkali metal salt to theresultingmixture of oil and soap stock, and thereafter continuously centrifugallyseparating said soap stock from said glyceride in the presence of saidadded solution for causing said soap stock to separate from .saidglyceride and iow continuously from the centrifugal separator employed.

8. The process of refining glyceride oils and fats containing free fattyacids and color impurities, which comprises, treating a glyceridesubstantially free of gummy materials with a color adsorbing material,separating said adsorbing madioxide and other vaporizable and gaseousmaterials to be separated from the resulting mixture to produce asubstantially dehydrated mixture of glyceride and soap stock, thereaftermixing a stream of said mixture with a stream of rehydrating liquid forsaid soap stock -and continuously centrifugally separating said soapstock from said glyceride in the presence of said rehydrating liquid.

11. The process of refining glyceride oils and fats containing freefatty acids and color impurities. which comprises. treating a glyceridesubstantially free of gummy materials with a color adsorbing material,separating said adsorbing material from said glyceride along with colorimpurities, thereafter neutralizing the free fatty acids of saidglyceride under conditions preterial from said glyceride along withcolor impurities, thereafter neutralizing the free fattyA acids of saidglyceride with a non-saponifying neutralizing agent, subjecting theresulting mixture of glyceride and soap stock to vacuum treatmentsufficient to remove water and other volatile materials from saidmixture, and continuously centrifugally separating said soap stock fromsaid glyceride in the presence of a rehydrating medium for said soapstock.

9. The process of refining glyceride oils and fats containing free fattyacids and color impurities, which comprises, treating a glyceridesubstantially free of gummy materials with a color adsorbing material,separating said adsorbing material from said glyceride along with colorimpurities, thereafter neutralizing the free fatty acids in saidglyceride with sodium carbonate, subjecting the resulting mixture ofglyceride and soap stock to vacuum treatment suihcient to remove waterand other volatile materials from said mixture, and continuouslycentrifugally separating said soap stock from said glyceride in thepresence of a rehydrating medium for said soap stock.

10. The process of refining glyceride oils and fats containing freefatty acids and color impurities, which comprises, treating a glyceridesubstantially free of gummy materials with a color adsorbing material,separating said adsorbing material from said glyceride along with colorimpurities, thereafter mixing an aqueous solution of sodium carbonatewith said glyceride under suicient vacuum to cause water, carbon ventingsubstantial saponiilcation of neutral glyceride, adding a solution of analkali metal salt to the resulting mixture of oil and soap stock, andthereafter separating the soap stock from said glyceride by differencein specic gravity, in the presence of said added solution.

12. The process of refining glyceride oils and fats containing gums.color impurities and free fatty acids, which comprises, removing saidgums from said glyceride, thereafter treating said glyceride with anadsorbent material for color impurities and removing said adsorbentalong with said color impurities from said glyceride, thereafterneutralizing the free fatty acids of said glyceride under conditionspreventing substantial saponiflcation of netural glyceride, adding asolution of an alkali metal salt to the resulting mixture of oil andsoap stock, and thereafter separating the soap stock from said glycerideby difference in specific gravity, in the presence of said addedsolution.

13. The process ofreilning glyceride oils and fats containing gums,color impurities and free -fatty acids, which comprises, removing saidgums and substantially all of said coloring matter from said glycerideoil, thereafter neutralizing the free fatty acids of said glycerideunder conditions preventing substantial saponiflcation of neutralglyceride, adding a solution of an alkali metal salt to the resultingmixture of oil and soap stock, and thereafter separating the soap stockfrom said glyceride by difference in specific gravity, in the presenceof said added solution.

14. 'Ihe process of refining glyceride oils and fats containing gums,color impurities and free fatty acids, which comprises, admixing adegumming agent containing a color reducing agent with said oil,separating the precipitated gums and coloring matter from said oil,thereafter neui tralizing the free fatty acids of said glyceride underconditions preventing substantial saponiflcation of neutral glyceride,adding a solution of an alkali metal salt to the resulting mixture ofoil and soap stock, and thereafter separating the soap stock from saidglyceride by difference in specific gravity, in the presence of saidadded solution.

BENJAMIN CLAYTON.

